1. Field of the Invention
This invention relates to a lift link gate having a plurality of individual tabular gate elements joined together.
The invention is primarily concerned with the structure and configuration of the individual tabular gate elements forming the lift link gate. Each gate element is provided with an outer skin of stamped metal. The gate element is preferably formed from a pair of stamped metal pieces which are sealed together to prevent the entry of extraneous or undesirable moisture to the interior thereof whereby to prevent damage to the material within the interior of the metal outer casing.
The outer casing of the tabular gate element may also be formed from a single stamped metal which does not form a complete closure but which substantially surrounds the interior portion. This type of gate element is preferably used in interior areas where undesirable moisture and/or the entry of undesirable extraneous matter is not a problem. However, even though in some instances, moisture may be a problem, it can also be used outdoors.
More particularly, the invention is concerned with a plurality of tabular gate elements which are joined together by means of joints, hinges, or the like, about a horizontally extending pivot axis. Specifically, each pair of adjacent elements are joined together by the aforesaid joints, and the gate elements are provided with pins or rollers which are adapted to slide in lateral guide tracks for guiding the gate from a vertical or vertically closed position, then along an arc into a horizontally open position which is orthogonally related to the closed position. When the lift link gate element is formed from the individual gate elements, the outer configuration of each gate element for all positions of the lift link gate element is configured that the spacing between adjacent gate elements is such to prevent a wedging of a finger between adjacent gate elements.
The invention is also concerned with a tabular gate element having its outer facing protected by sheet metal shells which can be preformed as half-shells and then snapped together to provide for a complete metal outer covering.
The tabular gate element may also be formed so that its outer facing is made from a single element which is larger than the half-shells but does not provide for a complete outer covering.
2. Description of the Prior Art
When the gate elements move from a vertical to a horizontal position, the adjacent gate elements have their spacing therebetween changed so that upper and lower edges of respective adjacent gate elements are spaced from each other in accordance with a mutual tilt and, as the gate elements come together along the arc, the rear end of one gate element approaches the front end of the next adjacent gate element and the fingers of a user may be wedged in and dangerous injuries may result. Examples of prior art in which this type of difficulty exists are those such as set forth in Stroup, U.S. Pat. No. 2,880,796, Giertsen, Federal Republic of Germany DE-OS 1509191.
The prior art has also proposed various solutions which while usable for other purposes can also be considered to avoid the wedging of a finger between adjacent gate elements, and yet none of these appear to be satisfactory. One suggested possibility for avoiding such injuries is disclosed in Austrian AT-PS 382,432. According to the disclosure of the Austrian publication, and other examples like it, specific edge sections are used to provide for a hinge-type joining of the gate elements, so that there remains at a front face of the closed gate, a distance between the upper and lower edges of adjacent gate elements, respectively; this is of a size generally to preclude the pinching of a finger. The disadvantage of the aforesaid heretofore known lift link gate is that the edge sections used are relatively costly and the closed gate has on its outer face inwardly recessed horizontal grooves which often are undesirable for aesthetic reasons.
The prior art has also provided for mutually facing edges of gate elements, a step so as to provide for a better heat insulation in the region of the closure (see, for example, Dover, Federal Republic of Germany DE-OS 2106063, Austrian AT-PS 369129). While these steps can improve the heat insulation, they do not help to avoid the danger of finger injuries.
During the prosecution of the parent application, Ser. No. 312,611, applicant became aware of U.S. Pat. No. 3,942,180 to Thill. This patent while providing for a spacing in certain positions of operation does not provide for a spacing which also helps to prevent the wedging of a finger or digit between the tabular gate elements. Moreover, in this patent, it is only possible to manufacture the outer metallic components or skin when the skin is made from aluminum and not steel because of the non-smoothly curving bends required of the metal.
Also cited was Crosswell, U.S. Pat. No. 3,198,242 which shows a recess that is not completely enclosed or protected from atmospheric elements by metal. A mating seal is provided to close the spacing between adjacent elements but a digit or finger is not prevented from being clamped.
There is other prior art known to the inventor from the parent application, Ser. No. 312,611. Specifically, reference is made to U.S. Pat. No. 3,198,242 to Crosswell which relates to an upwardly acting door which shows a depression in a first member complementary to a tooth-like projection in a second member and provided with resilient seal members in an attempt to prevent a portion of a limb from entering between the two members. In addition, Crosswell does not teach the use of two sheet metal shells independently formed. Crosswell has two outer plates held together by means of screws screwed into an intermediate section formed of a wood core or other insulating material to form a sandwich construction with the outer plates.